1、Designation: D 412 06a2Standard Test Methods forVulcanized Rubber and Thermoplastic ElastomersTension1This standard is issued under the fixed designation D 412; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revis
2、ion. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1NOTEAdded research report footnote to Section 19 editorial
3、ly in October 2008.2NOTERevised Eq 9 editorially in December 2008.1. Scope1.1 These test methods cover procedures used to evaluatethe tensile (tension) properties of vulcanized thermoset rubbersand thermoplastic elastomers. These methods are not appli-cable to ebonite and similar hard, low elongatio
4、n materials.The methods appear as follows:Test Method ADumbbell and Straight Section SpecimensTest Method BCut Ring SpecimensNOTE 1These two different methods do not produce identical results.1.2 The values stated in either SI or non-SI units shall beregarded separately as normative for this standar
5、d. The valuesin each system may not be exact equivalents; therefore eachsystem must be used independently, without combining values.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establ
6、ish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 1349 Practice for RubberStandard Temperatures forTestingD 1566 Terminology Relating to RubberD 3182 Practice for RubberMaterials, Equipmen
7、t, andProcedures for Mixing Standard Compounds and Prepar-ing Standard Vulcanized SheetsD 3183 Practice for RubberPreparation of Product Piecesfor Test Purposes from ProductsD 3767 Practice for RubberMeasurement of DimensionsD 4483 Practice for Evaluating Precision for Test MethodStandards in the Ru
8、bber and Carbon Black ManufacturingIndustriesE4 Practices for Force Verification of Testing Machines2.2 ASTM Adjunct:Cut Ring Specimens, Method B (D 412)32.3 ISO Standards:ISO 37 Rubber, Vulcanized and Thermoplastic Determina-tion of Tensile Stress-Strain Properties43. Terminology3.1 Definitions:3.1
9、.1 tensile setthe extension remaining after a specimenhas been stretched and allowed to retract in a specified manner,expressed as a percentage of the original length. (D 1566)3.1.2 tensile set-after-breakthe tensile set measured byfitting the two broken dumbbell pieces together at the point ofruptu
10、re.3.1.3 tensile strengththe maximum tensile stress appliedin stretching a specimen to rupture. (D 1566)3.1.4 tensile stressa stress applied to stretch a test piece(specimen). (D 1566)3.1.5 tensile stress at-given-elongationthe stress requiredto stretch the uniform cross section of a test specimen t
11、o agiven elongation. (D 1566)3.1.6 thermoplastic elastomersa diverse family of rubber-like materials that unlike conventional vulcanized rubbers canbe processed and recycled like thermoplastic materials.3.1.7 ultimate elongationthe elongation at which ruptureoccurs in the application of continued te
12、nsile stress.3.1.8 yield pointthat point on the stress-strain curve, shortof ultimate failure, where the rate of stress with respect tostrain, goes through a zero value and may become negative.(D 1566)1These test methods are under the jurisdiction of ASTM Committee D11 onRubber and are the direct re
13、sponsibility of Subcommittee D11.10 on PhysicalTesting.Current edition approved Dec. 15, 2006. Published January 2007. Originallyapproved in 1935. Last previous edition approved in 2006 as D 412 06.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service
14、at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Detailed drawings are available from ASTM Headquarters, 100 Barr HarborDrive, Conshohocken, PA 19428. Order Adjunct No. ADJD0412.4Available from American National
15、 Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.1.9 yield strainthe level of strain at the yield point.(D 1566)3.1.10 yield stressthe level of stress at the
16、yield point.(D 1566)4. Summary of Test Method4.1 The determination of tensile properties starts with testpieces taken from the sample material and includes thepreparation of the specimens and the testing of the specimens.Specimens may be in the shape of dumbbells, rings or straightpieces of uniform
17、cross-sectional area.4.2 Measurements for tensile stress, tensile stress at a givenelongation, tensile strength, yield point, and ultimate elonga-tion are made on specimens that have not been prestressed.Tensile stress, yield point, and tensile strength are based on theoriginal cross-sectional area
18、of a uniform cross-section of thespecimen.4.3 Measurement of tensile set is made after a previouslyunstressed specimen has been extended and allowed to retractby a prescribed procedure. Measurement of “set after break” isalso described.5. Significance and Use5.1 All materials and products covered by
19、 these test meth-ods must withstand tensile forces for adequate performance incertain applications. These test methods allow for the measure-ment of such tensile properties. However, tensile propertiesalone may not directly relate to the total end use performanceof the product because of the wide ra
20、nge of potential perfor-mance requirements in actual use.5.2 Tensile properties depend both on the material and theconditions of test (extension rate, temperature, humidity, speci-men geometry, pretest conditioning, etc.); therefore materialsshould be compared only when tested under the same condi-t
21、ions.5.3 Temperature and rate of extension may have substantialeffects on tensile properties and therefore should be controlled.These effects will vary depending on the type of material beingtested.5.4 Tensile set represents residual deformation which ispartly permanent and partly recoverable after
22、stretching andretraction. For this reason, the periods of extension andrecovery (and other conditions of test) must be controlled toobtain comparable results.6. Apparatus6.1 Testing MachineTension tests shall be made on apower driven machine equipped to produce a uniform rate ofgrip separation of 50
23、0 6 50 mm/min (20 6 2 in./min) for adistance of at least 750 mm (30 in.) (see Note 2). The testingmachine shall have both a suitable dynamometer and anindicating or recording system for measuring the applied forcewithin 62 %. If the capacity range cannot be changed for a test(as in the case of pendu
24、lum dynamometers) the applied force atbreak shall be measured within 62 % of the full scale value,and the smallest tensile force measured shall be accurate towithin 10 %. If the dynamometer is of the compensating typefor measuring tensile stress directly, means shall be provided toadjust for the cro
25、ss-sectional area of the specimen. Theresponse of the recorder shall be sufficiently rapid that theapplied force is measured with the requisite accuracy duringthe extension of the specimen to rupture. If the testing machineis not equipped with a recorder, a device shall be provided thatindicates, af
26、ter rupture, the maximum force applied duringextension. Testing machine systems shall be capable of mea-suring elongation of the test specimen in minimum incrementsof 10 %.NOTE 2A rate of elongation of 1000 6 100 mm/min (40 6 4 in./min)may be used and notation of the speed made in the report. In cas
27、e ofdispute, the test shall be repeated and the rate of elongation shall be at 5006 50 mm/min (20 6 2 in./min).6.2 Test Chamber for Elevated and Low TemperaturesThetest chamber shall conform with the following requirements:6.2.1 Air shall be circulated through the chamber at avelocity of 1 to 2 m/s
28、(3.3 to 6.6 ft/s) at the location of the gripsor spindles and specimens maintained within 2C (3.6F) of thespecified temperature.6.2.2 A calibrated sensing device shall be located near thegrips or spindles for measuring the actual temperature.6.2.3 The chamber shall be vented to an exhaust system ort
29、o the outside atmosphere to remove fumes liberated at hightemperatures.6.2.4 Provisions shall be made for suspending specimensvertically near the grips or spindles for conditioning prior totest. The specimens shall not touch each other or the sides ofthe chamber except for momentary contact when agi
30、tated bythe circulating air.6.2.5 Fast acting grips suitable for manipulation at high orlow temperatures may be provided to permit placing dumbbellsor straight specimens in the grips in the shortest time possibleto minimize any change in temperature of the chamber.6.2.6 The dynamometer shall be suit
31、able for use at thetemperature of test or it shall be thermally insulated from thechamber.6.2.7 Provision shall be made for measuring the elongationof specimens in the chamber. If a scale is used to measure theextension between the bench-marks, the scale shall be locatedparallel and close to the gri
32、p path during specimen extensionand shall be controlled from outside the chamber.6.3 Dial MicrometerThe dial micrometer shall conform tothe requirements of Practice D 3767 (Method A). For ringspecimens, see 14.10 of these test methods.6.4 Apparatus for Tensile Set TestThe testing machinedescribed in
33、 6.1 or an apparatus similar to that shown in Fig. 1may be used. A stop watch or other suitable timing devicemeasuring in minute intervals for at least 30 min, shall beprovided. A scale or other device shall be provided formeasuring tensile set to within 1 %.7. Selection of Test Specimens7.1 Conside
34、r the following information in making selec-tions:7.1.1 Since anisotropy or grain directionality due to flowintroduced during processing and preparation may have aninfluence on tensile properties, dumbbell or straight specimensshould be cut so the lengthwise direction of the specimen isD 412 06a22pa
35、rallel to the grain direction when this direction is known.Ring specimens normally give an average of with and acrossthe grain properties.7.1.2 Unless otherwise noted, thermoplastic rubber or ther-moplastic elastomer specimens, or both, are to be cut frominjection molded sheets or plaques with a thi
36、ckness of 3.0 60.3 mm. Specimens of other thickness will not necessarily givecomparable results. Specimens are to be tested in directionsboth parallel and perpendicular to the direction of flow in themold. Sheet or plaque dimensions must be sufficient to do this.7.1.3 Ring specimens enable elongatio
37、ns to be measured bygrip separation, but the elongation across the radial width ofthe ring specimens is not uniform. To minimize this effect thewidth of the ring specimens must be small compared to thediameter.7.1.4 Straight specimens tend to break in the grips if normalextension-to-break testing is
38、 conducted and should be usedonly when it is not feasible to prepare another type ofspecimen. For obtaining non-rupture stress-strain or materialmodulus properties, straight specimens are quite useful.7.1.5 The size of specimen type used will be determined bythe material, test equipment and the samp
39、le or piece availablefor test.Alonger specimen may be used for rubbers having lowultimate elongation to improve precision of elongation mea-surement.8. Calibration of the Testing Machine8.1 Calibrate the testing machine in accordance with Proce-dure A of Practices E4. If the dynamometer is of thestr
40、ain-gauge type, calibrate the tester at one or more forces inFIG. 1 Apparatus for Tensile Set TestD 412 06a23addition to the requirements in Sections 7 and 18 of PracticesE4. Testers having pendulum dynamometers may be calibratedas follows:8.1.1 Place one end of a dumbbell specimen in the uppergrip
41、of the testing machine.8.1.2 Remove the lower grip from the machine and attach it,by means of the gripping mechanism to the dumbbell specimenin the upper grip.8.1.3 Attach a hook to the lower end of the lower specimengrip mechanism.8.1.4 Suspend a known mass from the hook of the lowerspecimen grip m
42、echanism in such a way as to permit the massassembly to temporarily rest on the lower testing machine gripframework or holder (see Note 3).8.1.5 Start the grip separation motor or mechanism, as innormal testing, and allow it to run until the mass is freelysuspended by the specimen in the upper grip.
43、8.1.6 If the dial or scale does not indicate the force applied(or its equivalent in stress for a compensating type tester)within specified tolerance, thoroughly inspect the testing ma-chine for malfunction (for example, excess friction in bearingsand other moving parts). Ensure that the mass of the
44、lower gripmechanism and the hook are included as part of the knownmass.8.1.7 After machine friction or other malfunction has beenremoved, recalibrate the testing machine at a minimum of threepoints using known masses to produce forces of approximately10, 20 and 50 % of capacity. If pawls or rachets
45、are used duringroutine testing, use them for calibration. Check for friction inthe head by calibrating with the pawls up.NOTE 3It is advisable to provide a means for preventing the knownmass from falling to the floor in case the dumbbell should break.8.2 A rapid approximate calibration of the testin
46、g machinemay be obtained by using a spring calibration device.9. Test Temperature9.1 Unless otherwise specified, the standard temperature fortesting shall be 23 6 2C (73.4 6 3.6F). Specimens shall beconditioned for at least 3 h when the test temperature is 23C(73.4F). If the material is affected by
47、moisture, maintain therelative humidity at 50 6 5 % and condition the specimens forat least 24 h prior to testing. When testing at any othertemperature is required use one of the temperatures listed inPractice D 1349.9.2 For testing at temperatures above 23C (73.4F) preheatspecimens for 10 6 2 min f
48、or Method A and for 6 6 2 min forMethod B. Place each specimen in the test chamber at intervalsahead of testing so that all specimens of a series will be in thechamber the same length of time. The preheat time at elevatedtemperatures must be limited to avoid additional vulcanizationor thermal aging.
49、9.3 For testing at temperatures below 23C (73.4F) condi-tion the specimens at least 10 min prior to testing.TEST METHOD ADUMBBELL AND STRAIGHTSPECIMENS10. Apparatus10.1 DieThe shape and dimensions of the die for prepar-ing dumbbell specimens shall conform with those shown inFig. 2. The inside faces in the reduced section shall beperpendicular to the plane formed by the cutting edges andpolished for a distance of at least 5 mm (0.2 in.) from thecutting edge. The die shall at all times be sharp and free ofnicks (see 9.2).NOTE 4The conditio
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